Julia and Mojo are attempts at solving the "two language problem", which not every Python user actually has -- they're fine doing work exclusively in Python, not even using any of the libraries you're talking about.

Mojo in particular recognized to compete with Python they'd have to be a superset, then they backed of that goal when they realized it would be too hard.

So at the end of the day, Python has a value proposition and it cannot be entirely subsumed by other languages, because those languages make tradeoffs that move away from Python's value.